B Wastewater 2018 Study Guide Flashcards
What do ‘Worker Right to Know’ laws apply to?
Any plant that uses or stores chemicals (acids or bases)
Problem: Plant fecal coliform counts do not meet state standards. The chlorine supply is not the problem. There is adequate vacuum and chlorine feed. The chlorine contact tank has no solids build up and the Eff flow is below design. What is the most likely cause?
High chlorine demand from excessive nitrites in Eff
What is the most common potential hazard of working in a wastewater treatment laboratory?
Chemical Burns
A grit chamber is not working properly causing sand and grit to damage pumps. What is the most likely cause?
The length of the chamber is not adequate enough for the grit to settle out
FDEP approved continuous on line analyzing of reclaimed water effluent includes analyzing for?
pH, chlorine residual, & turbidity
What would you use to measure the alignment between a motor and a pump?
Dial indicator
In anaerobic digestion what does a pH decrease indicate?
Methane producers are reacting too slowly
What are bodies of water located at or near a river that are subject to tidal fluctuations?
Esturies
When nitrification increases in an activated sludge system, what other changes would be expected?
F/M=Decrease; MCRT=Increase; MLSS=Increase
According to state regulations a plant shall maintain a pH in the effluent after disinfection within what range?
6.0 - 8.5
What problems may develop during the injection of reclaimed wastewater into deep wells?
Contamination of groundwater
A gravity filter experiences rapid buildup of head loss. What could be a probable cause?
Incomplete backwash cycle
Even though a process control test is accurately performed, which one of the following could result in meaningless findings?
The sample not being representative of the process stream being sampled
An instrument used in a laboratory that measures the intensity of color or particular wavelength is a?
Spectrophotometer
When using breakpoint chlorination for ammonia removal, how many ppm of chlorine are needed to remove 1ppm of ammonia?
10
The strategy of allowing chlorinated water to stand for 24 to 48 hrs in the rapid sand filter and thoroughly backwashing the media is a remedy for?
Removing mudballs
How is the Fecal Coliform parameter evaluated?
By using the Most Probable Number (MPN) method, or the Membrane Filter (MF) method
When reading the level of a column of liquid in a graduated cylinder, burette, or manometer, you should?
Record the level of the bottom of the meniscus of the liquid being measured
To check for a sulfur dioxide leak you use?
Ammonia
In a suspended growth reactor used for Denitrification you need?
A carbon food source for proper metabolism of the organisms
By increasing the sludge feeding rate to your anaerobic digester, you decrease the detention time and?
Decrease alkalinity
In Ch. 62-699, FAC, Treatment Plant Classification and Staffing, wastewater treatment plants are classified in order to prescribe the lowest class of certified operators who will be permitted to operate the treatment plant. This classification system is based on what (2) two factors?
Permitted flow and treatment type
Lime is used more frequently for phosphorous removal than Aluminum Sulfate because aluminum sulfate is?
More expensive than lime
Before using the tubing in a lab the ends of the glass should be?
Flame polished
Evapotranspiration is?
Water removed from an area by plants and evaporation
When operating an Advanced Treatment facility using chemical treatment for solids removal you discover high flows entering the system. You should?
Prepare to feed a greater quantity of chemicals
The difference in pressure above and below the media of a gravity filter is called?
Head loss
How do you detect Hydrogen Sulfide?
Ammonia
Starting this type of pump against a closed valve can cause major damage to the pump, pump piping, the operator, or all three?
Positive displacement pump
According to FDEP Ch. 62-610, FAC, the definition: “water that has received at least secondary treatment and basic disinfection and is reused after flowing out of a domestic wastewater plant” describes as what?
Reclaimed water
Problem: Plant Eff coliform count fails to meet required standards for disinfection. Chlorine residual is normal. Disinfection supplies are not the problem. Probable cause is?
Contact time too short
A reduction of alkalinity across the secondary treatment process likely indicates?
Nitrification is occurring
When treating high organic loads, what process adjustments should be made?
Increase RAS
When operating an Advanced Treatment facility using chemical treatment for solids removal, you discover high flows entering the system. The first step you should take is to?
Prepare jar tests to determine dosage that will be good for decreased detention time
Why do pH levels drop during nitrification?
Alkalinity is destroyed
Preventive maintenance of electric motors includes?
Keeping the motor clean of dirt, dust, and moisture
Which process variables can be measured and/or controlled continuously?
Chlorine residual, D.O., & pH
If cake solids that are produced by a gravity belt filter thickener are too wet, what adjustments should be made?
Decrease belt speed and/or increase belt tension
What is the part of the inside of a pump that does not move?
Stator
What are coliform bacteria?
Indicators
Foaming in an aerobic digester, a microscopic examination shows very few filaments. What would be the cause?
Air rates too high
The most frequent problem encountered with a belt filter press is?
Washout
What is a fixed sample?
A sample preserved in the field upon collection
The volatile acid to alkalinity ratio of a properly operating anaerobic digester is?
0.1 part acid to 1.0 part alkalinity
In phosphorous removal using lime the pH should be at?
11
What does it mean when a belt filter press is washing out?
Water is overrunning over the sides of the belt
Problem: The plant Eff coliform count has failed to meet the required standards for disinfection. There is adequate chlorine residual. To confirm the cause, it is most relevant to check the?
Chlorine contact chamber for short circuiting.
What dosage of chlorine is fatal in just a few breaths?
1000 ppm (mg/l)
Which statement best describes at what speed a belt filter-press should be operated?
The ideal speed is the slowest the operator can maintain without washing out the belt
Problem: the plant Eff coliform count has failed to meet the required standards for disinfection. There is adequate chlorine residual. The best solution is to?
Install additional baffling
What would be the usual approach to measure the impact of a discharge to receiving waters?
Take a measurement in the upstream, unaffected, area and compare to a downstream affected area
Rapid accumulation on the surface of a single media sand filter results in very rapid head loss. The solution is?
Improve prior clarification
FAC 62-400.700(5). Soil requirements: The pH of the residuals soil mixture at the time residuals are applied shall be greater than?
5
When using polymer in a gravity thickening process for sludge, when would more polymer dosage be required?
When the hydraulic loading rate increases
What effect does nitrification have in the activated sludge process?
Decrease alkalinity and pH
What steps should the operator take if “Washing Out” occurs while operating belt press?
Lower flow rate and increase belt speed
It takes about 22% less O2 to process 1 lb of carbonaceous waste than 1 lb of nitrogenous waste. What does this indicate?
Additional D.O. is required to nitrify
To determine the location and amount of lowest dissolved oxygen downstream from a wastewater effluent discharge, it is necessary to?
Conduct an oxygen profile of the stream
A sand and gravel filter had been working well, but eventually head loss occurred. Performance did not improve significantly following backwashing. What is the most probable cause?
The backwash time was too short
Problem: the floating cover on a primary anaerobic digester appears to be tilting. Inspection of the rollers indicates that they are not the problem. While probing the annular space results in finding a thick scum accumulation. What should be done at this point?
Use chemicals or degreasing agents and hose down the scum blanket through the inspection ports
Which statement is the most correct concerning the dissolved oxygen content in water?
An increase in temperature causes a decrease in dissolved oxygen concentration
Chapter 62-601, Domestic wastewater treatment plant monitoring, states that onsite tests for total chlorine residual, pH, and can be performed under the direction of a certified operator or lab tech?
Dissolved oxygen
According to Ch 62-600, FAC, Domestic WW facilities, the basic disinfection requirement (using chlorine) is a?
0.5 mg/l minimum total chlorine residual after 15 minutes contact time at peak hourly flow
When does sludge bulking occur in the activated sludge process?
When filamentous bacteria dominate the population of microorganisms
The best process control method to prevent upset before it occurs when running an anaerobic digester system is?
The volatile acid / alkalinity ratio
According to FDEP chapter 62-600.400(4) (c) for basic level disinfection, any one sample may not exceed how many colonies per 100 ml sample?
800
What is gasification of a gravity thickener primarily caused?
Anaerobic sludge
If a sand drying bed has a problem with the media becoming clogged, what should the operator do first?
Rake the surface of the bed, removing the upper 2 to 3 inches of sand, and replace the sand with fresh sand
A treatment plant treating 5.0 MGD of domestic wastewater has primary settling, aeration tanks, final settling, aerobic digestion, and chlorine contact chambers. Which groups of tests are most important to assure proper operation and compliance with existing rules?
CBOD, Cl2, D.O., pH, Settleable solids, TSS, and Volatile solids
At what pH level does sulfide exist as 100% hydrogen sulfide gas?
Below a pH of 5
Which statement is correct concerning confined spaces?
Confined spaces are defined as those that provide difficult access to and/or exit from, combined with inadequate or deficient ventilation
Water quality criteria for wastewater reclaimed for public access includes?
High level disinfection
Most common cause of analysis failure when conducting a process test?
Sample incorrectly preserved
Why don’t you send 1% solids to an anaerobic digester?
Too much water
Problem: Chart with Day 1 and Day 2 scenario. There is rising sludge in the clarifier. What is the problem?
Increase in RAS conc.
How do you get rid of filaments?
Increase D.O.
What does not digest in a digester?
Hair
To remove ammonia you have to?
Raise the pH to between 10.8 and 11.5
When testing the D.O. in receiving waters what is least likely to cause a problem?
The method used, D.O. probe or Winkler
How do you sample primary sludge?
A composite sample while being pumped/ stirred
What happens when bacteria laden with phosphorus are placed in an anaerobic environment?
The phosphorus is released from the organisms’ cells
In phosphorus removal using lime what can happen when the pH drops?
Cloudy effluent and suspended floc particles
You have a rise in VA/Alk ratio in an anaerobic digester, the pH has dropped, what is the problem?
Overfeeding too much sludge into digester
You have a rise in VA/Alk ratio in an anaerobic digester, the pH has dropped, what is the solution?
Decrease solids loading
Problem: There is a homogenous sludge rising in clarifier. Solids settle slowly leaving clear effluent. SVI is increasing. There is low D.O. and low pH. What do you check?
Microscopic exam for filamentous organisms
Problem: There is a homogenous sludge rising in clarifier. Solids settle slowly leaving clear effluent. SVI is increasing. There is low D.O. and low pH. What is the solution?
Dose RAS with chlorine and monitor closely
A chlorinator with automatic proportional-to-flow controls will not feed enough chlorine to produce the proper residual. Sampling shows that at some times of the day there is an adequate residual, while at other times there is not. What do you check to confirm the problem?
Check the chlorinator feed rate
A chlorinator with automatic proportional-to-flow controls will not feed enough chlorine to produce the proper residual. Sampling shows that at some times of the day there is an adequate residual, while at other times there is not. What will correct the problem?
Repair the automatic control features
